Why does linux "freeze" during disk operations?

Question

linux

For disk operations that require a high load, the server freezes up to the console dump until the operation is completed. Encrypted the TrueCrypt disk - the speed dropped to 60 MB / s after 5 minutes. This is despite the fact that the normal speed of the file system for writing / reading is above 1200 MB / s.
Even cloning a VM (100GB) with a hyper takes a very long time, about half an hour, while the hyper's WEB interface falls off.
But Loading Windows 2012r2 in container takes less than 10 seconds, CrystalDiskMark inside container shows normal results
Given: HP E350ML, 4xSSD SAMSUNG in RAID-10 on p420i controller with r\w 60\40% cache
OS: Debian 8, ProxMox installed .
add. I noticed in htop that one of the 12 cores is 100% busy with "conversion", despite the fact that raw-> raw is being cloned. Then the console fell off.
add2. When copying a large file from directory to directory, copying starts at a speed of 800, then drops to almost 0 and everything hangs.
add3. On Windows with VeraCrypt - the same thing. The AES test gave out 2.6GB / sec, it is unlikely that the matter is in encryption. I also tried disabling the cache of the HDD controller, nothing really changes

Answer 1

It was in the EVO series of screws SAMSUNG. Be careful with this, colleagues. Not resolved.

Answer 2

https://lurkmore.to/12309

Answer 3

Something you put or set up sucks
Try to watch the motor and system logs, probably broken disks or cables

Answer 4

And what about without encryption?
I already forgot a lot, about 3 years ago I researched the topic of encryption under Linux, but then I concluded that the most reasonable choice was (actually regular) dm-crypt, since it supports multithreading. But how are things with TrueCrypt - we need to investigate more.